TWI825646B - Lens assembly - Google Patents

Abstract

A lens assembly includes a first lens, a second lens, and a third lens. The first lens is with positive refractive power. The second lens is with negative refractive power and includes a convex surface facing an image side. The third lens is with negative refractive power and includes a convex surface facing an object side. The first lens, the second lens, and the third lens are arranged in order from the object side to the image side along an optical axis. The lens assembly satisfies at least one of the following conditions: 2 < f/D1< 3.5; -3 < f3/f < -1; 0.5 mm < D1+D3 < 2.4 mm; 0.7 < f1/D1 < 2; wherein f is an effective focal length of the lens assembly, D1 is a maximum effective optical diameter of the first lens, D3 is a maximum effective optical diameter of the third lens, f1 is an effective focal length of the first lens, and f3 is an effective focal length of the third lens.

Description

Imaging lens(67)

The invention relates to an imaging lens.

The development trend of today's imaging lenses, in addition to the continuous development towards miniaturization, with different application requirements, also requires the characteristics of large field of view, high resolution and resistance to environmental temperature changes. Conventional imaging lenses can no longer meet today's requirements. Demand, especially when used in medical or micro photography, requires an imaging lens with a new architecture that can simultaneously meet the needs of miniaturization, large field of view, high resolution and resistance to environmental temperature changes.

In view of this, the main purpose of the present invention is to provide an imaging lens with a short overall length, a large field of view, a high resolution, and resistance to environmental temperature changes, but still has good optical performance.

The invention provides an imaging lens including a first lens, a second lens and a third lens. The first lens has positive refractive power, the second lens has negative refractive power and includes a convex surface facing an image side, and the third lens has negative refractive power and includes a convex surface facing an object side. The first lens, the second lens and the third lens are arranged in sequence from the object side to the image side along an optical axis. The imaging lens meets at least one of the following conditions: 2<f/D1<3.5; -3<f3/f<-1; 0.5mm<D1+D3<2.4mm; 0.7<f1/D1<2; where f is imaging The effective focal length of one of the lenses, D1 is The maximum optical effective diameter of one of the first lenses, D3 is the maximum optical effective diameter of one of the third lenses, f1 is the effective focal length of one of the first lenses, and f3 is the effective focal length of one of the third lenses. When the imaging lens of the present invention meets the above characteristics and conditions and does not require other additional characteristics or conditions, the basic functions of the imaging lens of the present invention can be achieved.

The first lens includes a convex surface facing the image side.

The first lens is a biconvex lens, the second lens is a meniscus lens, and the third lens is a meniscus lens.

The first lens may further include a convex surface facing the object side, the second lens may further include a concave surface facing the object side, and the third lens may further include a concave surface facing the image side.

The first lens is a meniscus lens, the second lens is a meniscus lens, and the third lens is a meniscus lens.

The first lens may further include a concave surface facing the object side, the second lens may further include a concave surface facing the object side, and the third lens may further include a concave surface facing the image side.

The imaging lens of the present invention may further include an aperture disposed between the object side and the first lens, wherein the imaging lens meets at least one of the following conditions: 80<f/SL<160; 0<SL/TTL<0.008; where, f is the effective focal length of the imaging lens, SL is the distance from the aperture to the object side of the first lens on the optical axis, and TTL is the distance from the object side of the first lens to an imaging surface on the optical axis.

The imaging lens meets at least one of the following conditions: 0.4<BFL/TTL<0.5; 0.8<(R11-R12)/(R11+R12)<1.7; -3<R11/R22<7; among them, BFL is the third lens The distance from the image side to the imaging surface on the optical axis, TTL is the distance from the object side of the first lens to the imaging surface on the optical axis, R11 is the radius of curvature of the object side of the first lens, R12 is the radius of curvature of the image side of the first lens, and R22 is the radius of curvature of the image side of the second lens.

The imaging lens of the present invention may further include an electronic photosensitive element disposed between the third lens and the image side, wherein the electronic photosensitive element includes a sensing surface, and the imaging lens meets the following conditions: 0.3<D3/IH<0.6; where, D3 is the maximum optically effective diameter of the third lens, and IH is the diagonal length within the effective pixel range of the sensing surface.

In order to make the above-mentioned objects, features, and advantages of the present invention more clearly understood, preferred embodiments are described in detail below along with the accompanying drawings.

1, 2: Imaging lens

ST1, ST2: Aperture

L11, L21: first lens

L12, L22: Second lens

L13, L23: third lens

CG1, CG2: Protective glass

IMA1, IMA2: imaging surface

SS1, SS2: sensing surface

OA1, OA2: optical axis

S11, S21: Aperture surface

S12, S22: Object side of first lens

S13, S23: First lens image side

S14, S24: Second lens object side

S15, S25: Second lens image side

S16, S26: Object side of third lens

S17, S27: Third lens image side

S18, S28: Protect the sides of glass objects

S19, S29: Protective glass side

11, 21: Electronic photosensitive element

Figure 1 is a schematic diagram of the lens configuration of the first embodiment of the imaging lens according to the present invention.

Figure 2 is a longitudinal aberration (Longitudinal Aberration) diagram of the first embodiment of the imaging lens according to the present invention.

Figure 3 is a field curvature diagram of the first embodiment of the imaging lens according to the present invention.

Figure 4 is a distortion diagram of the first embodiment of the imaging lens according to the present invention.

Figure 5 is a schematic diagram of the lens configuration of the second embodiment of the imaging lens according to the present invention.

Figure 6 is a longitudinal aberration diagram of the second embodiment of the imaging lens according to the present invention.

Figure 7 is a field curvature diagram of the second embodiment of the imaging lens according to the present invention.

Figure 8 is a distortion diagram of the second embodiment of the imaging lens according to the present invention.

The invention provides an imaging lens, including: a first lens with positive refractive power; a second lens has negative refractive power, and the second lens includes a convex surface facing an image side; a third lens has negative refractive power, and the third lens includes a convex surface facing an object side; wherein the first lens, the second lens and the third lens are arranged sequentially along an optical axis from the object side to the image side; the imaging lens meets at least one of the following conditions: 2<f/D1<3.5; -3<f3/f<-1; 0.5mm< D1+D3<2.4mm; 0.7<f1/D1<2; where, f is the effective focal length of one of the imaging lenses, D1 is the maximum optical effective diameter of one of the first lenses, D3 is the maximum optical effective diameter of one of the third lenses, f1 is one of the effective focal lengths of the first lens, and f3 is one of the effective focal lengths of the third lens.

Please refer to Table 1, Table 2, Table 4 and Table 5 below. Table 1 and Table 4 are respectively the relevant parameter tables of each lens according to the first to second embodiments of the imaging lens of the present invention. Table 2 and Table 5 is the relevant parameter table of the aspheric surface of the aspheric lens in Table 1 and Table 4 respectively.

Figures 1 and 5 are respectively schematic diagrams of lens configurations of the first and second embodiments of the imaging lens of the present invention. The first lenses L11 and L21 have positive refractive power and are made of plastic material. The image side surfaces S13 and S23 are convex surfaces, and the object side surfaces S12 and S22 and the image side surfaces S13 and S23 are all aspherical surfaces.

The second lenses L12 and L22 are meniscus-shaped with negative refractive power and are made of plastic material. The object side surfaces S14 and S24 are concave surfaces, the image side surfaces S15 and S25 are convex surfaces, and the object side surfaces S14 and S24 and the image side surfaces S15 and S25 are both Aspheric surface.

The third lenses L13 and L23 are meniscus lenses with negative refractive power and are made of plastic material. The object side surfaces S16 and S26 are convex surfaces, and the image side surfaces S17 and S27 are concave surfaces. The object side surfaces S16 and S26 and the image side surfaces S17 and S27 are both is an aspherical surface.

In addition, imaging lenses 1 and 2 meet at least one of the following conditions: 0.4<BFL/TTL<0.5; (1) 0.8<(R11-R12)/(R11+R12)<1.7; (2) -3<f3/f <-1; (3) -3<R11/R22<7; (4) 0.5mm<D1+D3<2.4mm; (5) 0.3<D3/IH<0.6; (6) 0<SL/TTL<0.008 ; (7) 0.7<f1/D1<2; (8) 80<f/SL<160; (9) 2<f/D1<3.5; (10) Among them, BFL is the first to second embodiments , the distance between the image side surfaces S17 and S27 of the third lenses L13 and L23 and the imaging planes IMA1 and IMA2 on the optical axes OA1 and OA2, TTL is the distance between the first lenses L11 and L21 in the first to second embodiments. The distance between the object side surfaces S12 and S22 and the imaging planes IMA1 and IMA2 on the optical axes OA1 and OA2, SL is the distance between the object side surfaces from the apertures ST1 and ST2 to the first lenses L11 and L21 in the first to second embodiments. The distance between S12 and S22 on the optical axes OA1 and OA2, R11 is the curvature radius of the object side surfaces S12 and S22 of the first lenses L11 and L21 in the first to the second embodiment, and R12 is the first embodiment In the second embodiment, R22 is the curvature radius of the image side surfaces S13 and S23 of the first lenses L11 and L21, and R22 is the curvature radius of the image side surfaces S15 and S25 of the second lenses L12 and L22 in the first embodiment to the second embodiment. A radius of curvature, f1 is an effective focal length of the first lenses L11 and L21 in the first to second embodiments, f3 is an effective focal length of the third lenses L13 and L23 in the first to second embodiments Focal length, f is one of the effective focal lengths of the imaging lenses 1 and 2 in the first to second embodiments, and D1 is In the first to second embodiments, D3 is the maximum optically effective diameter of one of the first lenses L11 and L21, and D3 is the maximum optically effective diameter of the third lens L13 and L23 in the first to second embodiments, IH is a diagonal length within the effective pixel range of the sensing surfaces SS1 and SS2 in the first to second embodiments. The imaging lenses 1 and 2 can effectively shorten the total length of the lens, effectively shorten the lens height, effectively improve the field of view, effectively resist environmental temperature changes, effectively improve the resolution, effectively correct aberrations, and effectively correct chromatic aberrations.

When condition (1) is met: 0.4<BFL/TTL<0.5, the lens height can be effectively shortened. When condition (2) is met: 0.8<(R11-R12)/(R11+R12)<1.7, the field of view can be effectively controlled and aberrations can be effectively corrected. When condition (3) is met: -3<f3/f<-1, aberrations can be effectively corrected and resolution improved. When the condition (4) is met: -3<R11/R22<7, the distortion can be effectively corrected. When condition (5): 0.5mm<D1+D3<2.4mm or condition (6): 0.3<D3/IH<0.6 is met, the lens volume can be effectively reduced. When condition (7) is met: 0<SL/TTL<0.008, the lens height can be effectively shortened.

The first embodiment of the imaging lens of the present invention will now be described in detail. Please refer to Figure 1. The imaging lens 1 sequentially includes an aperture ST1, a first lens L11, a second lens L12, a third lens L13 and an electronic lens along an optical axis OA1 from an object side to an image side. Photosensitive element 11. The electronic photosensitive element 11 includes a protective glass CG1 and a sensing surface SS1. During imaging, the light from the object side is finally imaged on the sensing surface SS1, and the sensing surface SS1 coincides with one of the imaging surfaces IMA1 of the imaging lens 1. According to the first to fifth paragraphs of [Embodiment], wherein: the first lens L11 is a biconvex lens, and its object side S12 is a convex surface; the object side S18 and the image side S19 of the protective glass CG1 are both flat; using the above lens, aperture ST1 and The design that satisfies at least one of the conditions (1) to (10) enables the imaging lens 1 to effectively shorten the total length of the lens, effectively shorten the lens height, effectively increase the field of view, effectively resist changes in ambient temperature, and effectively Improve resolution, effectively correct aberrations, and effectively correct chromatic aberrations.

Table 1 is a table of relevant parameters of each lens of the imaging lens 1 in Figure 1. When the refractive power and surface shape of each lens in Table 1 are met and conditions (1) to (10) are satisfied, it is a preferred embodiment of the present invention.

The aspheric surface concavity z of the aspheric lens in Table 1 is obtained by the following formula: z=ch ² /{1+[1-(k+1)c ² h ² ] ^1/2 }+Ah ⁴ +Bh ⁶ +Ch ⁸ +Dh ¹⁰ +Eh ¹² +Fh ¹⁴ +Gh ¹⁶ ; where: c: curvature; h: vertical distance from any point on the lens surface to the optical axis; k: cone coefficient; A~G: aspheric coefficient.

Table 2 is a table of relevant parameters of the aspheric surface of the aspheric lens in Table 1.

Table 3 shows the relevant parameter values of the imaging lens 1 of the first embodiment and the calculated values corresponding to conditions (1) to (10). From Table 3, it can be seen that the imaging lens 1 of the first embodiment can satisfy the condition (1 ) to the requirements of condition (10).

In addition, the optical performance of the imaging lens 1 of the first embodiment can also meet the requirements. As can be seen from Figure 2, the longitudinal aberration of the imaging lens 1 of the first embodiment is between -0.03mm and 0.01mm. It can be seen from Figure 3 that the field curvature of the imaging lens 1 of the first embodiment is between -0.03mm and 0.04mm. It can be seen from Figure 4 that the distortion of the imaging lens 1 of the first embodiment is between -15% and 1.5%. It is obvious that the longitudinal aberration, field curvature and distortion of the imaging lens 1 of the first embodiment can be effectively corrected, thereby obtaining better optical performance.

The second embodiment of the imaging lens of the present invention will now be described in detail. Please refer to Figure 5. The imaging lens 2 sequentially includes an aperture ST2, a first lens L21, a second lens L22, a third lens L23 and an electronic lens along an optical axis OA2 from an object side to an image side. Photosensitive element 21. The electronic photosensitive element 21 includes a protective glass CG2 and a sensing surface SS2. During imaging, the light from the object side is finally imaged on the sensing surface SS2, and the sensing surface SS2 coincides with one of the imaging surfaces IMA2 of the imaging lens 2. According to the first to fifth paragraphs of [Embodiment], the first lens L21 is a meniscus lens. The object side S22 of the mirror is concave; the object side S28 and the image side S29 of the protective glass CG2 are both flat; using the above lens, aperture ST2 and a design that meets at least one of the conditions (1) to (10), the image is formed Lens 2 can effectively shorten the total length of the lens, effectively shorten the lens height, effectively improve the field of view, effectively resist environmental temperature changes, effectively improve resolution, effectively correct aberrations, and effectively correct chromatic aberrations.

Table 4 is a table of relevant parameters of each lens of the imaging lens 2 in Figure 5. When the refractive power and surface shape of each lens in Table 4 are met and conditions (1) to (10) are satisfied, it is a preferred embodiment of the present invention.

The definition of the aspheric surface concavity z of the aspheric lens in Table 4 is the same as that of the first embodiment, and will not be described again here. Table 5 is a table of relevant parameters of the aspheric surface of the aspheric lens in Table 4.

Table 6 shows the relevant parameter values of the imaging lens 2 of the second embodiment and the calculated values corresponding to conditions (1) to (10). From Table 6, it can be seen that the imaging lens 2 of the second embodiment can satisfy the condition (1 ) to the requirements of condition (10).

In addition, the optical performance of the imaging lens 2 of the second embodiment can also meet the requirements. It can be seen from Figure 6 that the longitudinal aberration of the imaging lens 2 of the second embodiment is between -0.04mm and 0.04mm. It can be seen from Figure 7 that the field curvature of the imaging lens 2 of the second embodiment is between -0.02mm and 0.09mm. It can be seen from Figure 8 that the distortion of the imaging lens 2 of the second embodiment is between -15% and 3.5%. It is obvious that the longitudinal aberration, field curvature, and distortion of the imaging lens 2 of the second embodiment can be effectively corrected, thereby obtaining better optical performance.

Although the present invention has been disclosed in preferred embodiments, it is not intended to limit the present invention. Anyone familiar with the art can make various modifications and modifications without departing from the spirit and scope of the present invention. Therefore, the present invention The scope of protection shall be determined by the scope of the patent application attached.

1: Imaging lens

11: Electronic photosensitive element

ST1: Aperture

L11: first lens

L12: Second lens

L13:Third lens

CG1: Protective glass

IMA1: Imaging plane

SS1: Sensing surface

OA1: optical axis

S11: Aperture surface

S12: Object side of first lens

S13: First lens image side

S14: Second lens object side

S15: Second lens image side

S16: Third lens object side

S17: Third lens image side

S18: Protect the side of the glass object

S19: Protective glass image side

Claims (10)

An imaging lens includes: an aperture; a first lens with positive refractive power; a second lens with negative refractive power, the second lens including a convex surface facing an image side; a third lens with negative refractive power, the third lens includes A convex surface faces an object side; and an electronic photosensitive element; wherein the aperture, the first lens, the second lens, the third lens and the electronic photosensitive element are arranged along an optical axis from the object side to the image side. Arranged in sequence; wherein the electronic photosensitive element includes a sensing surface; wherein the imaging lens meets at least one of the following conditions: 2<f/D1<3.5; 0.5mm<D1+D3<2.4mm; 0.7<f1/D1<2 ;80<f/SL<160; 0<SL/TTL<0.008; 0.4<BFL/TTL<0.5; 0.8<(R11-R12)/(R11+R12)<1.7; 0.3<D3/IH<0.6; among which , f is the effective focal length of one of the imaging lenses, D1 is the maximum optical effective diameter of one of the first lenses, D3 is the maximum optical effective diameter of one of the third lenses, f1 is the effective focal length of one of the first lenses, SL is the distance between the aperture and the object side of the first lens on the optical axis, TTL is the distance from the object side of the first lens to an imaging plane on the optical axis, BFL is the distance from the image side of the third lens to the imaging plane on the optical axis, and R11 is the distance between the image side of the third lens and the imaging plane on the optical axis. The radius of curvature of the object side of a lens, R12 is the radius of curvature of the image side of the first lens, and IH is the diagonal length within the effective pixel range of the sensing surface. An imaging lens includes: a first lens with positive refractive power, the first lens being a biconvex lens; a second lens with negative refractive power, the second lens including a convex surface facing an image side; and a third lens with negative refractive power , the third lens includes a convex surface facing an object side; wherein the first lens, the second lens and the third lens are arranged in sequence along an optical axis from the object side to the image side; wherein the imaging lens at least Meet one of the following conditions: 2<f/D1<3.5; 0.5mm<D1+D3<2.4mm; 0.7<f1/D1<2; where f is the effective focal length of one of the imaging lenses, and D1 is the first lens is the maximum optical effective diameter of one of the third lenses, D3 is the maximum optical effective diameter of one of the third lenses, and f1 is the effective focal length of one of the first lenses. The imaging lens as claimed in any one of claims 1 to 2 of the patent application, wherein the first lens includes a convex surface facing the image side. The imaging lens as described in item 3 of the patent application, wherein: the second lens is a meniscus lens; and the third lens is a meniscus lens. The imaging lens as described in item 4 of the patent application, wherein: the first lens further includes a convex surface facing the object side; the second lens further includes a concave surface facing the object side; and the third lens further includes a concave surface Toward the image side. An imaging lens includes: a first lens with positive refractive power, the first lens including a concave surface facing the object side; a second lens with negative refractive power, the second lens including a convex surface facing an image side; and a third lens The lens has negative refractive power, and the third lens includes a convex surface facing an object side; wherein the first lens, the second lens and the third lens are arranged in sequence from the object side to the image side along an optical axis; wherein The imaging lens meets at least one of the following conditions: 2<f/D1<3.5; 0.5mm<D1+D3<2.4mm; 0.7<f1/D1<2; where D3 is the maximum optically effective diameter of one of the third lenses , D1 is the maximum optical effective diameter of one of the first lenses, f is the effective focal length of one of the imaging lenses, and f1 is the effective focal length of one of the first lenses. The imaging lens as described in item 6 of the patent application, wherein: the first lens is a meniscus lens; the second lens is a meniscus lens; and the third lens is a meniscus lens. The imaging lens as described in item 7 of the patent application scope, wherein: The second lens further includes a concave surface facing the object side; and the third lens further includes a concave surface facing the image side. Such as the imaging lens described in Item 1, Item 2 or Item 6 of the patent application scope, wherein the imaging lens meets the following conditions: -3<R11/R22<7; where R11 is the side surface of the object of the first lens is a radius of curvature, R22 is the radius of curvature of one of the image side surfaces of the second lens. For example, the imaging lens described in Item 1, Item 2 or Item 6 of the patent application scope, wherein the imaging lens meets the following conditions: -3<f3/f<-1; where f is the effective focal length of the imaging lens , f3 is the effective focal length of one of the third lenses.

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